The phosphorelay signal transduction pathway in the initiation of Bacillus subtilis sporulation

✍ Scribed by James A. Hoch

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 624 KB
• Volume: 51
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/jcb.240510111

✦ Synopsis

The formation of spores in Bacillus subtrhs is a developmental process under genetic control. The decision to either divide or sporulate is regulated by the state of phosphorylation of the SpoOA transcription factor. Phosphorylated SpoOA (SpoOA -P) is both a repressor and an activator of transcription depending on the promoter it is affecting. SpoOA -P is the end product of the phosphorelay, a signal transduction system linking environmentcat information to the activation of sporulation. Activation or deinhibition of two ATP-dependent kinases, KinA and KinB, to phosphorylate the SpoOF secondary messenger initiates the phosphorelay. SpoOF -P i s the substrate for the SpoOB protein, a phosphoprotein phosphotransferase which transfers the phosphate group to SpoOA. The SpoOA -P formed from this pathway orchestrates transcription events during the initial stage of spore development through direct effects on a variety of promoters and through the use of other transcription factors, termed transition state regulators, whose activity it controls. Because commitment to sporulation has serious cellular programming consequences and i s not undertaken capriciously, the phosphorelay is subject to a variety of complex controls on the flow of phosphate through itscomponents. D 1993 Wiley-Liss, inc.